ICCIPPP Berichtzusammenfassung

Final Activity Report Summary - ICCIPPP (EST at the interface between particle physics and cosmology)

The ICCIPPP project allowed us to bring together the expertise in two world class research groups, the Institute for Computational Cosmology and the Institute for Particle Physics Phenomenology, both at Durham University, working at the interface between particle physics and cosmology.

There had previously been little interaction between members of the groups, but the Marie Curie host fellowship provided the impetus needed to build new capacity in training and research. We recruited five high quality fellows to study for PhDs as part of their training and four fellows for short term fellowships. The covered research topics addressed a wide range of open questions in particle physics and cosmology, such as:

1. what was driving the accelerating expansion of the Universe? 2. how would we be able to distinguish between a change to Einstein's law of gravity or a new field in the Universe called dark energy? 3. how could we explain the strength of gravity compared to other forces? 4. was the cold dark matter cosmology compatible with observations of galaxies in the early universe, which was sensitive to the nature of the dark matter and the way in which structures built up in the dark matter? 5. how did supermassive black holes grow and what role did they play in the formation of galaxies in a cold dark matter universe?

A large part of research training was in high performance computing. Computer simulations were the only way to accurately model the growth of cosmic structure due to gravity. Early simulations were instrumental in shaping cosmologists' ideas about the nature of the dark matter which was believed to dominate the mass of the universe, showing that massive neutrinos could not make up the bulk of the dark matter. In the ICCIPPP project we produced the first consistent calculations of the formation of structure in a universe in which the cosmological constant component was replaced by a dynamical scalar field, which was more palatable to particle physicists. We explored how competing cosmologies might be distinguished by forthcoming galaxy surveys. The different signatures of the models were subtle and a clear understanding of the systematics was essential in case the new measurements were to be successfully and correctly interpreted.

Our project brought together experts in cosmology and particle physics and allowed them to overcome the obstacles to understanding the cutting edge in one another's fields. The training we provided the fellows combined research specific instruction and complementary training. Our fellows successfully completed PhD theses, in shorter than the typical time. They took part in international meetings, schools and conferences and gave presentations on their work at such meetings, raising their profile within the subject. The fellows also published refereed papers on their work in the main international journals in the subject. As a result of this project we built a new joint activity between the two research institutes which made up the Ogden Centre and, by the time of the project completion, we had already secured some independent funding from a private donor to sustain this activity through a new PhD studentship.